Method for making aromatic bis(ether anhydride)s

ABSTRACT

Aromatic bis(ether anhydride)s can be made by a nitro displacement of an N-substituted nitrophthalimide with an alkali (diphenoxide to produce an intermediate aromatic bis(etherphthalimide). Hydrolysis of the aromatic bis(etherphthalimide) to the corresponding tetra-acid salt followed by acidification and dehydration, results in the production of the aromatic bis(ether anhydride). These anhydrides can be used as intermediates for making polyimides. The intermediate aromatic bis(etherphthalimide) can be employed as a plasticizer in polyimide resins.

[4 1 Apr. 22, 1975 METHOD FOR MAKING AROMATIC BIS(ETHER ANHYDRlDElSlnventors: Darrell R. Heath, Pittsfield. Mass;

Tohru Takekoshi, Scotia, N.Y.

General Electric Company, Schenectady, NY.

Filed: Mar. 30, 1973 Appl. No: 346,473

Assignee:

U.S. Cl 260/346.3; 260/304 R; 260/78; 260/326 A; 260/326 N; 260/516;260/520; 260/326 S Int. Cl. C07c 63/48; C07c 63/00 Field of Search260/3463, 326 S References Cited UNITED STATES PATENTS 1/1974 Heath ctal. 260/3463 Primary E.\'aminerHenry R. Jiles Assistant Examiner-Bernardl. Dentz Attorney, Agent. or FirmWilliam A. Teoli; .loseph T. Cohen;Jerome C. Squillaro v [57] ABSTRACT Aromatic bis(ether anhydride)s canbe made by a nitro displacement of an N-substituted nitrophthalimidewith an alkali (diphenoxide to produce an intermediate aromaticbis(etherphthalimide). Hydrolysis of the aromatic bis(etherphthalimide)to the corresponding tetra-acid salt followed by acidification anddehydration, results in the production of the aromatic bis(etheranhydride). These anhydrides can be used as intermediates for makingpolyimides. The intermediate aromatic bis(etherphthalimide) can beemployed as a plasticizer in polyimide resins.

12 Claims, No Drawings METHOD FOR MAKING AROMATIC BIS(ETHER ANHYDRIDE)S'The present invention relates to a method for making aromatic bis(ether anhydride)s from N-substituted nitrophthalimides by a nitrodisplacement reaction with bisphenolate. followed by phthalimide ringopenings to the tetra acid salt. acidification. and subsequentdehydration. The intermediate aromatic bis(etherimide) is also provided.

CH Br CH Br The aromatic bis(ether anhydride)s which can be made by themethod of the present invention have the following formula,

. c 8 o O-R-O where R is a divalent aromatic radical having from 6-30carbon atoms.

In accordance with the present invention the aromatic bis( etheranhydride )s of formula (I) can be made by (I) effecting nitrodisplacement of a nitrophthalimide of the formula.

with an alkali diphenoxide of the formula.

M-O-R-0-M to produce an intermediate aromatic bis(etherphthalimide). (2)hydrolyzing the aromatic bis(etherphthalimide) with base to produce atetra-acid salt, (3) acidifying the tetra-acid salt to produce thetetra-acid, and

(4) dehydrating the tetra-acid to the aromatic bis(ether anhydride)where R is as previously defined, M is a metal ion of an alkali metalselected from the class consisting of sodium. potassium, lithium. etc.and R is a monovalent organo radical selected from the class consistingof C alkyl radicals. and organic radicals hav- .ing from 6-20 carbonatoms. selected from the class consisting of aromatic hydrocarbonradicals and halogenated derivatives thereof.

Radicals included by R are more particularly CH CH Br vCH Br Br Br Brand (b) divalent organic radicals of the general formula where X is amember selected from the class consisting of divalent radicals of theformulas, -C ,H

Br CH and an organic amine, RNi-l where R is as previously defined inthe presence of refluxing acetic acid. Included by such organic aminesare, for example, an line, toluidine, ete., methylaminc, ethylamine,etc. Ni-

trophthalimides included by formula (11) are, for example,N-phenyl-3-nitrophthalimide, N-phenyl-4- nitrophthalimide,N-methyl-3-nitrophthalimide. N-butyl-4-nitrophthalimide. etc.

A significant feature of the present invention is that anitrophthalimide of formula (11) and an alkali diphenoxide of formula(111) can be reacted at from 5C to 100C and preferably ambient to 70C toproduce the corresponding aromatic bis(etherphthalimide) intermediate.This result is quite surprising in view of the teaching of Lyman R.Caswell in the Robert A. Welch Foundation Annual Report. Houston. Texas1970), on page 58, which suggests a significant difference between thereactivities of 3- and 4-nitro-N-substituted phthalimides with sodiummethoxide. A further advantage of the present invention is demonstratedby the teaching of German Offenlegungschrift 2.155.431, showing thattemperatures of at least 150C are required to couple N-substituted4-chlorophthalimides with alkali metal dihydroxy cyclic compounds whereas indicated above. the method of the subject invention allows fortemperatures as low as 5C.

Included by the aromatic bis(ether anhydride)s of formula (1), arecompounds selected from O O v? @v 8 O-R O o '9 'c' /c\ 0/ .Ca 0 (VI) 80--R 8 where R is as previously defined. These dianhydrides can beemployed to make polyetherimides which can be injection molded to usefulproducts.

Included by the alkali metal salts of the above described alkalidiphenoxides of formula (I) are sodium and potassium salts of thefollowing dihydric phenols 2.2-bis-(2-hydroxyphenyl)propane;2.4-dihydroxydiphenylmethane; bis-(Z-hydroXyphenyUmethane;2,2-bis-(4-hydroxyphenyl)propane hereinafter identified as bisphenol-A"or "BPA;" l,1-bis-( 4-hydroxyphenyl )ethane; l,1-bis-( 4-hydroxyphenyl)propane;

2,2-bis-(4-hydroxyphenyl)pentane; 3.3-bis-(4-hydroxyphenyl)pentane;4,4-dihydroxybiphenyl; 4,4'-dihydroxy-3,3.5,5'-tetramethylbiphenyl;2.4'-dihydroxybenzophenone; 4,4'-dihydroxydiphcnylsulfone;2,4'-dihydroxydiphenylsulfone; 4.4-dihydroxydiphenyl sulfoxide;4,4'-dihydroxydiphenyl sulfide; hydroquinone;

resorcinol; 3,4'-dihydroxydiphenylmethane; 4,4'-dihydroxybenzophenone;

and 4,4'-dihydroxydiphenylether.

1n the practice of the invention, reaction is effected between thenitrophthalimide, or nitroimide" of formula 11. and the alkalidiphenoxide or diphenoxide to produce an aromatic bis(etherphthalimide)or bisimide." The bisimide is thereafter hydrolyzed with base to thetetra-acid salt, which is thereafter acidified to the tetra-acid; thetetra acid can then be dehydrated to the corresponding aromaticbis(ether anhydride) or bisanhydride" of formula 1.

Reaction between the nitroimide and diphenoxide to produce the bisimidecan be effected under an inert gas atmosphere such as nitrogen at 5C to100C under substantially anhydrous conditions and in the presence ofdipolar aprotic organic solvent such as dimethyl sulfoxide,N,N?dimethylformamide. N-methylpyrrolidine, N,N-dimethylacetamide, etc.Mixtures of such solvents with non-polar solvents such as toluene,chlorobenzene. etc. also can be employed. Reaction time can vary betweenone minute to 100 minutes or more depending upon temperature, degree ofagitation, etc. A proportion of from 1.8 to 2.5 moles of nitroimide, permole of diphenoxide can be used.

Hydrolysis of the bisimide to the tetra-acid slt can be effected underreflux conditions in the presence of a base such as an alkali hydroxide,for example, sodium hydroxide, etc. Reaction time can vary from 1 to 24hours or more depending upon reactants, degree of agitation,temperature, etc. The organic amine by-product can be removed bystandard procedures, such as steam distillation, etc. In addition, therate of hydrolysis is greatly accelerated by carrying out the reactionat above atmospheric pressures at temperatures in the range of from 100to 220C.

The tetra-acid salt can thereafter be acidified with a mineral acid,such as a dilute aqueous solution of hydrochloric acid, etc. Theresulting tetra-acid canbe dehydrated by standard techniques. Forexample, reflux.- ing with a dehydrating agent such as acetic anhydride,etc. the dianhydride can be recrystallized by standard 5 procedures.

In order that those skilled in the art will be better able to practicethe invention, the following examples are given by way of illustrationand not by way of limitation. All parts are by weight.

. of dimethylsulfoxide, 10 ml of benzene, and 0.8 g of sodium hydroxideas a 50% aqueous solution was stirred and heated to reflux in a nitrogenatmosphere over a Dean Stark trap for 5 hours. The benzene was distilleduntil the temperature of the reaction mixture exceeded C and the mixturewas cooled to 15C. Then 5.36g

(0.02 mol) of N-phenyl-3-nitrophthalimide and ml of dimethylsulfoxidewere added. The solution was stirred for minutes at room temperature and30 minutes at 50C. cooled, and added to 600 ml of water. The gummy solidwhich separated was extracted into methylene chloride and the organicsolution dried with sodium sulfate. filtered. and evaporated to leave anoil. The oil solidified when slurried with hot ethanol to give 5.6g (85%yield) of crude product. Recrystallization from acetonitrile gave finewhite needles melting at 187-188.5C. Anal. Calcd. for C. H ..N O C.77.0; H. 4.47; N. 4.18. Found: C. 77.1; H. 4.6; N. 4.2. Based on theabove preparation and elemental analysis. there was obtained 2.2-bis[4-(N-phenylphthalimid-3- oxy )phenyl l-propane.

A mixture of 81.5g of 2.2-bisl4-(N- A mixture of 459g of 2.2-bis[4-(2.3-

-dicarboxyphenoxy)pheny11propane. 400 cc of glacial acetic acid. and 25cc of acetic anhydride was stirred at reflux for 3 hours. There wasobtained 34.2g of an off-white solid when the mixture was filtered. Theproduct was recrystallized from toluene/acetic acid to give 3 t 0g ofwhite needles; m.p. 186l87.5C. Anal. Calcd. for C ,H ..O,.: C. 71.5; H.4.]. Found: C. 71.4; H. 3.8. Based on method of preparation andelemental analysis. the product was 2.2-bis[4-(2.3-dicarboxyphenoxy)phenyl]propane dianhydride.

EXAMPLE 2 A mixture of 29.8g (0.131 mol) of bisphenol-A. 10.44g ofsodium hydroxide in the form of a 50% aqueous solution. 250 cc ofdimethylsulfoxide. and 66 cc of toluene was stirred in a nitrogenatmosphere at reflux for 7 hours Final drying was effected by refluxingthe toluene over a recirculating trap filled with calcium hydride. Thetoluene was removed by distillation and the reaction mixture was cooledto 60C. Then 70.0g (0.26 mol) of N-phenyl-4-nitrophthalimide and 250 ccof dimethylsulfoxide were added; the resulting solution was stirred at60C for 45-minutes. There was added 25 cc of glacialacetic acid; thereaction mixture was then diluted with 1.400g of water. A fine solidseparated; it was isolated by filtration. washed with water. and dried.After recrystallization from acetonitrile and from benzene there wasobtained 44.4g of white needles. m.p. 214C. Anal. Calcd. for C H No z C.77.0; H. 4.51; N. 4.18. Found: C. 76.7; H. 4.5; N. 4.1. Based on methodof preparation and elemental analysis the product was2.2-bis[4-(N-pheriylphthalimid 4-oxy phenyl]- propane. I i V A zmixtureL of 60.2g of 2.2-bisl4-(N- phenylphthalimid-4-oxy)phenyllpropane.57.37g of an aqueous 50% sodium. hydroxide solution. and 350 cc of waterwas heated for 25 hours at 160l75C under 150 psi pressure. The mixturewas then steam distilled for 45 minutes. The aqueous residue wasacidified with hydrochloric acid. A product separated from the aqueoussolution. which was washed with water and recrystallized from 50% aceticacid. There was obtained 329g of product; m.p. 208-2l6C. Anal Calcd. forC H O C. 66.9; H. 4.3. Found: C. 66.5; H. 4.4. Based on method ofpreparation and elemental analysis. there was obtained 2.2-bis[4-(3.4-

l0 dicarboxyphenoxy)phenyll-propane.

A mixture of 24.7g (0.05 mol) of 2.2-bis[4-(3.4-dicarboxyphenoxy)phenyl]propane. 250 cc of glacial acetic acid. and12.8g of acetic anhydride was stirred at reflux for 2.5 hours. Thesolution was concentrated on a rotary evaporator. A white crystallineproduct separated on cooling. The product was isolated by filtration.washed with cold acetic acid. and dried in vacuo. The material wasrecrystallized from a toluene/acetic acid mixture to give 20g ofproduct. m.p. l87l90C. Anal Calcd. for C H O C. 71.5; H. 4.1. Found: C.72.0; H. 3.8. Based on method of preparation and elemental analysis. theproduct was 2.2-bis[4-(3.4- dicarboxyphenoxy)phenyllpropane dianhydride.

EXAMPLE 3 A mixture of 1.10g (0.01 mol) of hydroquinone. 0.8g of sodiumhydroxide as a 50% aqueous solution. 30 ml of dimethylsulfoxide. and 10ml of benzene was stirred in a nitrogen atmosphere at reflux over a DeanStark trap for 3 hours. The benzene was removed by distillation untilthe temperature of the reaction mixture exceeded 140C; the mixture wasthen cooled to 15C. There were added 5.36g (0.02 mol) of N-pheny1-3-nitrophthalimide. and 20 ml of dimethylsulfoxide. The solution wasstirred for 20 minutes at l5-20C. 20 minutes at 30C and for 20 minutesat 40C. After cooling the reaction mixture. there was added thereto 400m1 of water. A crude product was isolated by filtration. The crudeproduct was dissolved in 700 ml of boiling ethylene glycol and separatedfrom the cold solution as fine white needles. The recrystallized productwas dried in vacuo at l 10C. There was obtained 3.8g yield) of product.m.p. 3l23l3C. Anal. Calcd. for C .H- N O C. 73.9; H. 3.62; N. 5.07.Found: C. 73.8; H. 3.9; N. 5.0. Based on method of preparation andelemental analysis the product was l.4-bis(N-phenylphthalimid-3-oxy)benzene.

A mixture of 54.2g of l.4-bis(N-phenylphthalimid-3- oxy)benzene. 54.4gof a 50% aqueous sodium hydroxide solution, and cc of water was stirredat reflux for 24 hours. There was added with stirring at reflux anadditional 200g of water. The mixture was stirred for 2 more days. Themixture was steam distilled. A product separated when the aqueoussolution was acidified. The crude material was isolated by filtration togive 46.6g of product. The product was then mixed with 55g of 50% sodiumhydroxide and 500g of water. It was heated at C for 2 hours under sealedconditions. Acidification of the cooled solution with concentratedhydrochloric acid gave 41.1g of crude product. Recrystallization from a50/50 mixture of water-acetic acid gave 39.3g of white powder; m.p.305-3l5C. The product was found to be the acetic acid adduct of 1.4-bis(2.3-dicarboxyphenoxy)benzene. Anal. Calcd. for C H O 2CH COOH: C,55.92; H. 3.97. Found: C. 56.0; H. 4.1. Acid number: Calculated. 10.74meq/g; Found. 10.4 meq/g.

A mixture of 39.3g (010901 mol) of l,4-bis(2,3-dicarboxyphenoxy)benzene. 400 cc of glacial acetic acid. and 25 cc ofacetic anhydride was stirred at reflux for 3 hours. The solution wascooled and filtered. Based on method of preparation. the product wasl.4-bis(2.3-

dicarboxyphenoxy)benzene dianhydride.

EXAMPLE 4 A series of bisimides were prepared in accordance with thepresent invention by effecting the nitrodisplacement of anitrophthalimide of formula ll, with an alkali diphenoxide of formulaIII. The bisimides were included by the following formula,

o /'c'\ '0' (VII R N @oaog NR C c (i b I where R and R are as previouslydefined.

The following tables show the bisimides prepared where R and R are asdefined in Table l and the calculated values for the elemental analysisare shown in Table 2.

TABLE 1 Properties of Bisimitles |n.p. R R' 1.5.* (C) 187.5- l1.4-Benzene n-Butyl 3 188.5

270- (2) l.3-Benzene Phcnyl 3 272 303- (3) 4.4-Biphenyl Phenyl 3 304.5

3] l- (4) 4.4'-Biphenyl Phenyl 4 3 l 3 239.5- (5 4.4'-DiphenyletherPhenyl 3 242.5

305.5 (6) 4.4 '-Diphenylether Phenyl 4 308.5 (7) 4.4 '-Diphenyl- Phenyl3 284- sulfide 285 (8) 4.4'-Diphcnyl- Phenyl 4 229- sulfide 230 (9)Z.2-Bis( 4-phenyl n-Butyl 3 propane 95-98 l0) 2.2-Bis( 4-phenyl n-Butyl4 propane 88-90 236.5- l l 4.4'-Benzophenone Phenyl 3 238.5 l2)2.2-Bis(4-phenyl)- Methyl 3 208.5

propane 209 l 3 2.2-Bis( 4-phenyl Methyl 4 I29- propane 130 lsnmericStructure TABLE 2 Elemental Analysis of the Above Bisimides C H N S(Calcd.)

TABLE 2 Continued Elemental Analysis of the Above Bisimides c H N S(Calcd.)

The above bisimides can be employed as plasticizers for organic polymerssuch as polyvinylchloride. polyimides. etc; these bisimides canwithstand oxidation at high temperatures.

Although the above examples are limited to only a few of the very manybisimides which are provided by the present invention, it should beunderstood that the bisimides provided by the invention are broadlyshown by formula VI].

In addition to the dianhydride shown by the above examples. it should beunderstood that the method of the invention broadly provides dianhydrideshown by formula I.

What we claim as new and desire to secure by Letters 30 Patent of theUnited States:

1. A method for making an aromatic-bis(ether anhydride) which comprisesa. effecting the nitro displacement of a nitrophthalimide of theformula,

II C 1 N0 \/N-R II O with an alkali diphe hoxide of the formula,

bon radicals and halogenated derivatives thereof. and

C alkyl radicals.

2. A method in accordance with claim 1, where the alkali diphenoxide isthe diphenoxide of bisphenol-A. 3. A method in accordance with claim 1,where the alkali diphenoxide is the diphenoxide of hydroquinone. 4. Amethod in accordance with claim 1, where R is phenyl.

5. A method in accordance with claim 1, where R is methyl.

. 9 6. A method in accordance with claim I, where M is A mfilhod inaccordance with Claim Where sodium. N-methyl 3-nitrophthalimide is used.

7. A method in accordance with l i 1, where ll. A method in accordancewith claim 1. where N-phenyl-3-nitr0phthalimide i dN-methyl-4-nitr0phthalimide is used.

8. A method in accordance with l i 1, wh 12. A method in accordance withclaim I. where a N-phenyl-4-nitrophthalimide is used. 5 mixture ofN-methyl-3-nitrophthalimide and N-methyi 9. A method in accordance withclaim I. where a *nitmphthalimide is usedmixture ofN-phenyl-3-nitrophthalimide and N-phenyl- 4-nitrophthalimide is used.

1. A METHOD FOR MAKING AN AROMATIC-BIS(ETHER ANHYDRIDE) WHICH COMPRISESA. EFFECTING THE NITRO DISPLACEMENT OF A NITROPHTHALIMIDE OF THEFORMULA,
 1. A method for making an aromatic-bis(ether anhydride) whichcomprises a. effecting the nitro displacement of a nitrophthalimide ofthe formula,
 2. A method in accordance with claim 1, where the alkalidiphenoxide is the diphenoxide of bisphenol-A.
 3. A method in accordancewith claim 1, where the alkali diphenoxide is the diphenoxide ofhydroquinone.
 4. A method in accordance with claim 1, where R1 isphenyl.
 5. A method in accordance with claim 1, where R1 is methyl.
 6. Amethod in accordance with claim 1, where M is sodium.
 7. A method inaccordance with claim 1, where N-phenyl-3-nitrophthalimide is used.
 8. Amethod in accordance with claim 1, where N-phenyl-4-nitrophthalimide isused.
 9. A method in accordance with claim 1, where a mixture ofN-phenyl-3-nitrophthalimide and N-phenyl-4-nitrophthalimide is used. 10.A method in accordance with claim 1, where N-methyl-3-nitrophthalimideis used.
 11. A method in accordance with claim 1, whereN-methyl-4-nitrophthalimide is used.